U-Pb dating of detrital zircon grains in the Paleocene Stumpata Formation, Tethyan Himalaya, Zanskar, India

The sediments deposited on the northern margin of Greater India during the Paleocene allow the timing of collision with the Spontang Ophiolite, the oceanic Kohistan-Dras Arc and Eurasia to be constrained. U-Pb dating of detrital zircon grains from the Danian (61-65 Ma) Stumpata Formation shows a provenance that is typical of the Tethyan Himalaya, but with a significant population of grains from 129 7 Ma also accounting for similar to 15% of the total, similar to the synchronous Jidula Formation of south central Tibet. Derivation of these grains from north of the Indus Suture can be ruled out, precluding India's collision with either Eurasia or the Kohistan Dras before 61 Ma. Despite the immediate superposition of the Spontang Ophiolite, there are no grains in the Stumpata Formation consistent with erosion from this unit. Either Spontang obduction is younger than previously proposed, or the ophiolite remained submerged and/or uneroded until into the Eocene. The Mesozoic grains correlate well with the timing of 130 Ma volcanism in central Tibet, suggesting that this phase of activity is linked to extension across the whole margin of northern India linked to the separation of India from Australia and Antarctica at that time. Mesozoic zircons in younger sedimentary rocks in Tibet suggest a rapid change in provenance, with strong erosion from within or north of the suture zone starting in the Early Eocene following collision. We find no evidence for strongly diachronous collision from central Tibet to the western Himalaya. (C) 2013 Elsevier Ltd. All rights reserved.